Full featured MUD server with all the trimmings.
Arianne is an engine to develop multiplayer online games like Stendhal
A Tile-based Game Engine written in C# mimicing retro consoles.
JamochaMUD is a Java MUD/MUCK client.
Provides a full suite of clients and servers for virtual worlds.
Fast paced action RPG with retro graphics style
A simple telnet (and possibly SSH) server
Java client for TradeWars 2002
CoffeeMudForAI is plaform to design AI in